I've been downloading a few mods lately, and while I'm fairly new to it I haven't had any problems til now, but after the last few I put on my game today I encountered a rather strange graphical glitch. Upon loading my most recent save, I was greeted by a rather strange landscape, the entire surface of Cyrodiil was reformatted with a skin comprised of tiles that appear to be a portion of the world map, including the Imperial City and Cheydinhal, and the color is mostly green with a bit of pinkish-purple on the edge. I'm rather stumped as to how this happened, as none of the mods I installed had anything to do with the environment of the world, and I'd like to know how I could fix this. The weird floor/ground is only on the surface of the outside world (including the ground within the city), inside buildings and all trees/grass/walls/plants/rocks are still normal. Any ideas/solutions?

Normally this is caused when your texture size is set to anything other than "Large". Try changing your texture size first of all.

Well, I tried it and it didn't work, and now Heronymous Lex is acting weird in the Thieves Guild quest where you plant the Bust in the informant's cupboard, he went up to the cupboard but said "There's nothing here!" and walked back out, leaving me stuck in the "cutscene" mode where you can only move the camera. I hope I didn't accidentally delete or overwrite anything important...

Post your load order then, from Wrye Bash, and we'll take a look .

As I recall, this usually occurs if you haven't installed the latest official patch. Sometimes the installation fails yet doesn't say so, so you might believe the patch is fully installed when in fact it is not.

You were right, I had to re-install it and it's all fixed now, thanks guys!